1. Field of the Invention
The present invention relates to the light treatment chambers for treating objects placed therein, and more particularly to the sealing the light treatment chamber from the outside environment. Even more particularly, the present invention relates to a hatch for sealing an opening of the light treatment chamber from the outside environment.
2. Discussion of the Related Art
A light treatment chamber is a device in which objects are treated with light to deactivate microorganisms on the objects. A passthrough treatment device is generally known in the art as a treatment device including a treatment chamber into which non-sterile objects are placed into from a “contaminated” or non-sterile environment, treated within the treatment chamber, and then retrieved out of the treatment chamber into a “clean” or sterile environment, such as within an isolation barrier or chamber. Passthrough treatment devices are commonly used in medical and pharmaceutical applications where items, such as operating instruments or pharmaceutical devices, are placed within the treatment chamber, treated, and then retrieved into the sterile environment. Thus, contaminants from the non-sterile environment are deactivated prior to entry into the sterile environment. Typically only one side of the passthrough treatment chamber, or door to the passthrough treatment chamber, is open at a time, to prevent the free flow of air-borne contaminants into the sterile environment.
Many techniques are used to deactivate organisms on the surface of the objects prior to being inserted into a sterile environment. One example is through the use of continuous wave ultraviolet light (also referred to as UV light) directed at the object to be transferred into the sterile environment. The ultraviolet light is typically provided by low-pressure Mercury vapor lamps, which emit UV light at about 253 nm. An example of such an ultraviolet passthrough device is shown in U.S. Pat. No. 5,446,289, entitled ULTRAVIOLET PASSTHROUGH STERILIZATION DEVICE, issued to Shodeen et al. (hereinafter referred to as the '289 patent). The object is placed into the treatment chamber of the UV passthrough device from a non-sterile environment through a first door. The first door is closed; thus, sealing the treatment chamber from the non-sterile environment and then the treatment chamber is irradiated with the UV light, generated by Mercury lamps, for about 30 seconds to 3 minutes at about 2000-6000 micro watts per square centimeter. For most applications, this is sufficient to deactivate most organisms on the object. However, sterilization of the object and the treatment chamber is not achieved in such devices, with microbial deactivation being only on the order of 4 or 5 logs reduction (whereas 6 to 7 logs reduction is generally recognized as sufficient to constitute sterilization). The object is then removed from the treatment chamber by opening a second door that is exposed to the sterile environment and removing the item.
An important feature of the passthrough device, such as that shown in the '289 patent, is that the treatment chamber, also referred to as the “treatment cell” or the “treatment zone”, must be sealed from both the non-sterile environment and the sterile environment when microorganisms are being treated with, e.g., the ultraviolet light. And, at least one end of the treatment chamber must always be sealed to prevent the flow of microorganisms between the sterile and non-sterile environments. There are many types of sealing devices available for use in such passthrough devices. The most common is a sealed door system, as shown in the '289 patent, having a first and second door. Thus, the first door has an open position such that an operator can access the treatment chamber (e.g. to place an object to be sterilized therein) through an opening and a closed position such that the first door engages the opening in the treatment chamber. Similarly, the second door also has an open position such that the operator can access the treatment chamber from the sterile environment via another opening (e.g. removing the object having been sterilized within the treatment chamber) and a closed position, such that the second door engages the other opening in the treatment chamber.
Both the first and second doors incorporate molded seals and gaskets to effectuate the seal between the openings of the treatment chamber and the respective doors; thus, sealing the sterile environment from the non-sterile environment. Mechanical pressure is typically applied to each door against the portion of the treatment chamber that contacts the door (i.e. the contact area between the door and the treatment chamber is typically at the opening). Typically, a seal or gasket is positioned at the opening of the treatment chamber and/or another seal or gasket is positioned around the edges of the door. This mechanical pressure is typically the force applied as the door is snugly closed against the opening, or within the opening.
Additionally, the door is designed with some type of locking device that maintains this mechanical pressure on the door against the contact area between the door and the treatment chamber. Examples of such locking devices include a latch system, such as found in common mechanical door designs, or a lever or arm that is rigidly moved in position over the door once closed to physically hold the door in position against the appropriate seals or gaskets with a desired amount of force to effectuate the seal.
One problem associated with sealed door systems and other mechanical sealing devices is that they may be structurally complicated requiring precisely cut or molded seals and/or gaskets that conform to the specific dimension of the door and/or the area that the seals are designed to contact, e.g. the seals must conform precisely to an opening of the treatment chamber. Thus, if one or more seals are imperfect in shape, the sealing of the treatment chamber may not be complete. Furthermore, over time, the seals or gaskets may physically degrade due to repeated exposure to the light source used in the treatment; thus, compromising the effective seal created between the door and opening to the treatment chamber.
Additionally, another problem is that the door itself or the structure holding the door, e.g. the hinge or arm handle, may become slightly deformed (e.g. warped due to the weight of the door or other pressure applied to the door), which may affect the evenness of the pressure applied to the contact area between the door and opening to the treatment chamber. For example, in the closed position, the door may not apply an even amount of pressure to all areas of the seals at different contact points. Furthermore, the locking device, e.g. a latch or lever, may not hold the door against or within the opening to the treatment chamber with an even amount of pressure or force, or even hold the door with the appropriate amount of force. For example, although the seals, the door, the hinges, the arms, etc., may be structurally perfect and be able to seal the door within the opening to the treatment chamber with the proper alignment and pressure, the locking device may not properly retain the door within the opening with the appropriate pressure due to physical deformities in the locking device. Thus, disadvantageously, the seals may not be held together effectively and the seal formed may be compromised.
What is needed is a structurally simple and easily replaceable sterilized seal for a light treatment chamber, such as a passthrough treatment device, as an alternative to the common sealed door system using molded seals or gaskets. The present invention advantageously addresses the above and other needs.